PW: The Devil in the White City and your bestseller, Isaac's Storm, take place within a few years of each other. What is it about the late 19th century that appeals to you?

Erik Larson: I do love the Gilded Age. It was a period in which people thought they could do anything, and, more often than not, they succeeded. That's tremendously appealing. It was not a guarded time. People spoke with candor, and they wrote long letters to each other. It's a researcher's dream.

PW: Why did the 1893 Chicago World's Fair have such an impact?

EL: Richard Harding Davis, the famous globe-trotting journalist, said it had an impact equivalent to that of the Civil War, although I think there's a fair amount of hyperbole there. It was very important to show off what all these technical and artistic minds in America had achieved. You had this intense, billowing sense of both regional and national pride. Chicago was intensely proud of its achievements in commerce, and yet also had kind of an inferiority complex in terms of its level of refinement. For Chicago, to make this "the greatest fair in history" was something that all of Chicago's movers and shakers bent their will to achieve. A lot of people came together to show off the best of everything America had to offer—how could it not have the impact that it did? But then you also had the architecture, where everything came together to create something that was almost surreal in its beauty—so much so, that there were reports of people entering the Grand Court of the fair and bursting into tears, it was so beautiful.

PW: Some consider H.H. Holmes to be America's first serial killer. What do you think of that?

EL: Holmes specifically took advantage of all of the things that were making the Gilded Age a revolutionary period, trains and the availability of credit and so forth. That's how I would put it, that he was the first urban American serial killer.

PW: Why do you think he isn't better known to us?

EL: You know, I don't know. I was struck by that. Jack the Ripper in London was doing his killing only a few years before Holmes turned up with his World's Fair Hotel in Chicago. Jack the Ripper, according to the best estimates, killed probably five women and became an icon of evil forever. Here's this guy Holmes, who kills many more, a number that will never be determined but some have estimated as high as 200—which I think is high, but several dozen is probably very reasonable. I keep coming back to the idea that there was something too dark about these events to fit what America wanted to believe about itself.

PW: Were you surprised at how long it took for people to realize that all these disappearances were connected to Holmes?

EL: Oh, stunned. It's absolutely bizarre that this character and his house did not come to the attention of the police in a serious way until well after the fair. However, Chicago was growing so fast, the police were nowhere near large enough or skilled enough to deal with the kind of crime that was occurring. People disappeared daily and not necessarily because they were murdered or kidnapped. The city was absolutely in flux, a thousand trains entering the city every day. It's almost as if the police said, "Okay, certain things we will pay attention to, the disappearance of the son or daughter of a merchant prince, but otherwise, we'll take note and that's it."